Contrast Adaptation and Representation in Human Early Visual Cortex Export

@article{citeulike:1269837, abstract = {Summary The human visual system can distinguish variations in image contrast over a much larger range than measurements of the static relationship between contrast and response in visual cortex would suggest. This discrepancy may be explained if adaptation serves to recenter contrast response functions around the ambient contrast, yet experiments on humans have yet to report such an effect. By using event-related fMRI and a data-driven analysis approach, we found that contrast response functions in V1, V2, and V3 shift to approximately center on the adapting contrast. Furthermore, we discovered that, unlike earlier areas, human V4 (hV4) responds positively to contrast changes, whether increments or decrements, suggesting that hV4 does not faithfully represent contrast, but instead responds to salient changes. These findings suggest that the visual system discounts slow uninformative changes in contrast with adaptation, yet remains exquisitely sensitive to changes that may signal important events in the environment.}, author = {Gardner, Justin L. and Sun, Pei and Waggoner, Allen R. and Ueno, Kenichi and Tanaka, Keiji and Cheng, Kang}, citeulike-article-id = {1269837}, citeulike-linkout-0 = {http://www.sciencedirect.com/science/article/B6WSS-4GWS8KH-J/2/077f2da3de1acf8e25e7fc69de25828e}, day = {18}, journal = {Neuron}, keywords = {brightness, vision}, month = {August}, number = {4}, pages = {607--620}, posted-at = {2007-05-01 08:43:58}, priority = {2}, title = {Contrast Adaptation and Representation in Human Early Visual Cortex}, url = {http://www.sciencedirect.com/science/article/B6WSS-4GWS8KH-J/2/077f2da3de1acf8e25e7fc69de25828e}, volume = {47}, year = {2005} }

TY - JOUR ID - citeulike:1269837 L3 - citeulike-article-id:1269837 N2 - Summary The human visual system can distinguish variations in image contrast over a much larger range than measurements of the static relationship between contrast and response in visual cortex would suggest. This discrepancy may be explained if adaptation serves to recenter contrast response functions around the ambient contrast, yet experiments on humans have yet to report such an effect. By using event-related fMRI and a data-driven analysis approach, we found that contrast response functions in V1, V2, and V3 shift to approximately center on the adapting contrast. Furthermore, we discovered that, unlike earlier areas, human V4 (hV4) responds positively to contrast changes, whether increments or decrements, suggesting that hV4 does not faithfully represent contrast, but instead responds to salient changes. These findings suggest that the visual system discounts slow uninformative changes in contrast with adaptation, yet remains exquisitely sensitive to changes that may signal important events in the environment. IS - 4 JF - Neuron EP - 620 TI - Contrast Adaptation and Representation in Human Early Visual Cortex VL - 47 SP - 607 KW - brightness KW - vision AU - Gardner, Justin AU - Sun, Pei AU - Waggoner, Allen AU - Ueno, Kenichi AU - Tanaka, Keiji AU - Cheng, Kang PY - 2005/08/18/ UR - http://www.sciencedirect.com/science/article/B6WSS-4GWS8KH-J/2/077f2da3de1acf8e25e7fc69de25828e ER -